U.S. Pat. No. 3,381,928 (White) teaches a bookrest including a flat base with a raised retainer, a platen used to support reading material, and a swingable strut. The strut is hingedly connected to the platen and engages with a plurality of extensions to allow different reading angles. Each of the extensions of White has a same relatively low height. If the strut is accidently dislodged from contact with an extension, in particular, the extension furthest from the connection of the platen to the raised retainer, the weight of the platen and any material on the platen can cause the platen to collapse.
U.S. Design Pat. No. D513,008 (Takizawa) and U.S. Design Pat. No. D639,816 (Bau) teach a stand for a personal computer and a stand for an electronic device, respectively. Like the '928 patent, the preceding design patents lack a means for preventing the accidental dislocation and collapse noted above.